Improvements in turbojet units, including means for by-passing air on its way from the compressor to the turbine of the unit



Aug. 28, 1956 v REMGER 2,760,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ONITS WAY FROM THE COMPRESSOR TC THE TURBINE OF THE UNIT Filed July 17,1951 3 Sheets-Sheet 1 INVENTDR g- 1956 v. RENIGER 2,750,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ONITS WAY FROM THE COMPRESSOR TO THE TURBINE OF THE UNIT Filed July 17,1951 s Sheets-Sheet 2 Aug. 28, 1956 v. RENIGER 2,760,336

IMPROVEMENTS IN TURBOJET UNITS, INCLUDING MEANS FOR BY-PASSING AIR ONITS WAY FROM THE COMPRESSOR TO THE TURBINE OF THE UNIT Filed July 17,1951 3 Sheets-Sheet 3 toward c/aw/zsream al'oe of compressor-.5

lNVENTDR BY I 1 Unite tates Patent G INIPRGVEMENTS 1N TURBO-YET UNITS,INCLUD- ING BEANS FDR Edi-PASSING AIR ON ITS WAY FRQM THE COMPRESSGR TTIE TURBINE 015 THE UNIT Victor Reniger, Chatillon-sous-Bagneux, France,assignor to )fiice National dEtudes et de Recherches Aeronautiques (0.N. E. R. A.), Chatillon-sous-Bagneux, France, a society of FranceApplication an 17, 1951, Serial No. 237,093

Claims. (21. 60-3554) The present invention relates to turbo-jet unitsin which air is by-passed on its way from the compressor to the turbine,for instance for feeding braking nozzles.

It is known that braking nozzles, used for reducing the speed of jetaircrafts, in particular for landing, may be supplied with air collectedfrom the outlet of the compressor. However, if no precautions are taken,by-passing of air from the outlet of the compressor involves seriousdrawbacks concerning the efiiciency of the unit.

The object of the present invention is to provide a turbo-jet unit ofthe type above described which avoids these drawbacks.

Preferred embodiments of my invention will be hereinafter described withreference to the accompanying drawings, given chiefly by way of example,and in which:

Fig. l is a diagrammatic sectional view of a turbo-jet unit madeaccording to my invention;

Fig. 2 is a corresponding diagram showing the air distribution, aportion of this view being a section on the line HH of Fig. l; v i

Fig. 3 is a diagrammatic plan view showing air distribution cut-oifmeans in two combustion chambers supposed for the sake of simplificationto be located in the same plane;

Fig. 4 diagrammatically shows an automatic air by-pass control deviceaccording to my invention;

Figs. 5 and 6 are diagrammatic detail views on a larger scale.

, from the compressor toward the turbine.

In the example illustrated by Figs. 1 to 3, it is supposed that threecombustion chambers, designated by 2a, 2b, 20, respectively, are thusbrought out of action when the braking nozzles are to be operated.

My device includes, in this embodiment, a set of shutters 5 pivotallydisposed between fixed partitions 6 and located ahead of said combustionchambers 2a, 2b and 20.

Fixed partitions 6a, 6b, 6c and 6d, Which also cooperate with shutters5, limit said combustion chambers.

Shutters 5 are actuated through a ring 7 movable on an annular bearingsurface 8 fixed on the outer casing of the unit. Between ring 7 andshutters 5 are provided links 9 rigid with the spindles 5a of saidshutters 5 and the slotted ends 9a of which engage pins 7a carried byring 7.

Ring 7 may be operated either manually or automatically. In the exampleshown, ring 7 is actuated by means of a jack 10 operated by oil underpressure supplied from a valve device 11 manually controlled by thePatented Aug. 28, 1956 operator by means of a lever L. Oil underpressure from a suitable source enters this valve 11 through a conduit12 and it leaves it through conduits 13 and 14. This oil is fed to jack10 through either of conduits 15 and 16 and it escapes therefrom throughthe other of these conduits.

The means for by-passing air from the stream flowing from the compressortoward the turbine and sending this by-passed air to the braking nozzles17 include three by-pass pipes 18a, 18b, 18c, starting from the conduitleading from the compressor to said shutters 5, at points locatedupstream of said shutters, these by-pass pipes,

leading to a common conduit 19 connected through branch pipes 20 withthe braking nozzles 17.

The inlet of each of these nozzles 17 is provided with a throttle valve21. These throttle valves 21 are to be opened when shutters 5 are beingclosed. Advanta geously, the means for controlling shutters 5 and thosefor controlling throttle valves 21 are interconnected.

For this purpose, each of the throttle valves 21 is operated, as shownfor one of them, by means of a hydraulic jack 22 supplied with oil inparallel with jack 10, for instance through branch pipes 15a and 16a incom- .munication with pipes 15 and 16 respectively (Figs. 2

and 6).

Fuel is fed to each combustion chamber 2 through a pipe 23 controlled bya valve 24. Valves 24 are, same as throttle valves 21, operated throughhydraulic jacks 24a supplied with oil through conduits 15b and 16bconnected with distributing pipes 15a, 16a respectively (Figs. 2 and5)., t

Braking nozzles 17 are to be supplied, simultaneously with compressedair, with fuel fed through pipes 25 controlled by valves 26respectively. Each valve 26 is operated through a hydraulic jack 26asupplied with oil through conduits 15c, 16c branching off from conduits15a, 16a respectively.

Advantageously, the, turbo-jet unit is provided, in its jet nozzle, witha cone 27 slidable longitudinally in the -jet nozzle'for varying theoutlet section of said jet nozzle.

Control of the longitudinal displacements of this come is preferablyinterconnected with that of shutters 5. For this purpose, cone 27carries a nut 28]: prevented from rotating about its axis and in meshwith a screw 28a rotatable about itsaXis but prevented from slidinglongitudinally, rotation of this screw being obtained from a shaft 29actuated by a pinion 30, which may be the gear of a hydraulic motor 31inserted in the oil circuit constituted by pipes 15d and 16d.(Figs. 1and 2).

In the above described example of a device according to my invention, acertain amount of air can therefore be by-passed from the compressor 3to the braking nozzles 17 by operating lever L to place a given numberof combustion chambers temporarily out of action.

I may also, according to my invention, vary the relative amount of airwhich is thus by-passed. This result can be obtained by providing meansfor bringing the various elements above referred to (such as shutters 5,throttle valves 21, etc.) into any of a plurality of positionsintermediate between the fully closed one and the fully open one..

However, I consider that it is more advantageous to vary the number ofcombustion chambers brought out of action, the number of braking nozzlesbrought into action being simultaneously and correspondingly varied.

According to a preferred embodiment of my invention,

the supply of air from the compressor to the respective braking nozzlesis automatically controlled in response to variations of the compressedair pressure downstream I of the compressor, these variations beingproduced by the operator by varying the number of combustion chambersthat are out of service. a

Fig. 4 shows automatic control means complying with this condition. Thisarrangement corresponds to the case of an airplane p'rovidedwithfourbraking nozzles adapted tobe operated independently; Fig. 4 showsthe means forcontrolling the feed of air to only two of these nozzles,

' a by means of hydraulicjacks' 32a and 320. i The two other nozzleswould be controlledsimilarly.

These jacks are controlled'by means-of an automatic valve systemincluding-a casing 33, a diaphragm '34, a

spring 3 5 and a slide valve 3 6. One of the faces of diaphragm 34 isconnected through a conduit 37 with the ment it would be only 2.24 kgs.per sq. cm. Thus, the thrust I can obtain by means of the brakingnozzles. is about one half of the thrust developed by the turbo-jetunder normal working conditions, whereas, with the conventionalarrangement, it is about one fourth thereof.

In a general manner, while I have, in the above description, disclosedwhat I deem to be practical and efficient embodiments of my invention,it should be well'under stood that I do not wish to be limited theretoas there might be changes made inthe arrangement; disposition and formofthe parts without departing from the principle of the presentinvention as comprehended within the scope of the accompanying claims;

space on the downstream side of compressor 3 and is 7 thereforesubjected to the pressure of theeompresscd air,

and the other face is subjected to the atmospheric pressure, J

owing to the provision of ports 38. Spring 35 balances the differencebetween these pressures.

'The casing 36:; of slide valve 36 is supplied with oil under pressurethrougha conduit 39. The discharged oil escapes through either ofconduits 4i) and 41.

Valve 3636a operates a relay, valve device 42, through two conduits 43and 44. a

This relay valve device 42 is supplied with oil under pressure throughconduit 45, whereas the discharged oil escapes through either ofconduits 46 and 47.

, The four braking nozzle control jacks are suppliedwith oil underpressure respectively through conduits 48a, 48b,

48c, 48d for displacement in one direction and through conduits 49a,49b, 49c, 49d for displacement in theother direction. 7

Whenthe operator actuates shutters 5, and forinstance when he opens onlythose corresponding to one combustion chamber, the compressedairpressure on the downstream side of the compressortends to rise, wherebyslide valve 36 moves downwardly. Qilunder pressure from 1 'conduit39 isthen supplied to cylinder 42 through con- "What fl claim is:

1. In combination with a turbo-jet unit including a com: pressor, aturbine, a jet nozzle atthe outlet of saidturbine,

means for driving said compressor operative by saidturbine, a piuralityof combustion chambers mounted inparallelbetween the outlet of saidcompressor' and the 2. in combination, on an aircraft, a plurality ofbrak 7 ing nozzles, a turbo-jet unit including a compressor, a turduit43. Piston 42a move's down and causes slide valve 42b to connect conduit49a with feed conduit 45. The

piston of jack 32a is'thus moved down, which opens the r I throttlevalve 21 of'the corresponding braking nozzle. 7

The throttle valves of the other braking nozzles are closed.

However, theamount of air by-passed fromthe downstream side of thecompressor causes to restore the downstream compressed air pressure toits normal value. When this value is reached, slide valve 36 cuts offthe connection between conduits? and the source of oil under pressure(conduit 39). fiston 42a and slide valve 42b remain stationary in theposition they now occupy.

If the operator increases the number of combustion chambers placed outof service, piston 42a is again moved sively bringing the brakingnozzles into action.

When the number of combustion chambers placed out f @5011 s e eoperations above described are reversed.

' 'Of course, instead of 'closing some of the combustion .chamberslmight as well reduce the section of flow thr ugh a o mi ,Theadvantage ofmy device is as follows: 7

Considering the case of a turbo-jet unit working under normal conditions(for instance the pressure on the down stream side or" the compressorbeing 5 kgs; per sq. cm.

and the temperature upstream of the turbine 800 Cl), calculation showsthat with my device, the. maximum amount of air that can be lay-passed(in the limit, case where the propulsion energy of the'turbo-jet becomeszero) is about 31% of the airflow rateunder normal working conditions,whereas with the conventional arrangement, it was only 22%, whichcorresponds to a gain of 50% over the results previously obtained.Furtherm r yt i by'p s d ith m device s the normal pressure existingdownstream of the compressor, i. e. 5

kgs. per sq. -cm whereas; with the conventional arrangedownwardly,together withi'slid e valve 42b, thus succes bine, a jet nozzle at theoutlet ofsaid turbine, meansfor driving said compressor operativeibysaid turbine, a plurality of combustion chambers mounted in' parallelbetween theoutletEof saidcempresscr and the inlet of said 7 turbine, andmeans 'for feeding fuel to saidcombustion chambers respectively, andadevice for feeding air'under pressure frorn'said compressor to saidbraking nozzles which comprises means for cutting oif communicationbetween theoutlet of said compressor and any number i of said chamberssmaller than the total number thereof,

means for cutting off the fuel feed means of said chamber, conduitmeansfor by-passing a portion of the;com-: pressed airfed at the outlet ofsaid compressor'tolsaid brakingnozzle, valve means in'said conduit meansfor controlling said nozzles, means responsive tovariations of thepressure at the outlet Said-compressor for succes-.

sivcly opening said'valve means as said outlet pressure rises, 'andmeansoperatiyely connectedwith said valve means for operating saidcommunication cut-off means 7 and said fuel feed cut-of meanssimultaneously and corl sra r nsl ith the i br s s f se il 3. incornbination, on an aircraft, at least one braking nozzle, a turbo-jetunitincluding a compressor, a turbine, I a jet nozzle at the outlet ofsaid turbine, a cone coaxial with said nozzle slidable therein so, thatlongitudinal movethem thereofvaries the outlet section of saidjetnozzle,

means for driving said compressor operative by said turbine, a pluralityof combustion chambers mounted in parallel between the ,outlet of saidcompressor and the inlet of said turbine, and means for feeding fuel tosaid combustion chambers respectively, and adevice for feed ing airunder pressure fro-m said compressor to said brakinertia-ads w i h mor eesa Pu 0E m ni a en b ween t r u st fsai cam e nd least'one of saidcharnbers, means-for cutting off the fuel feed means of said chamber,means for sliding said cone in said jet nozzle to reduce the,outlet'section thereof,

conduit means for by-passing toward said braking nozzle V V a portion of.the compressed air fed at the outlet of said compressor, and 'meansforfsimultaneously and coneispondingly opcratingthe four'lastmentionedmeans,

7 4. In a device as claimed in claim. 1,,means tori-varyingytheoutletsection.of said'iiet, nozzle, and meansflrespon sive tooperation of said bypassing means to operate said nozzle section varyingmeans.

5. In a device as claimed in claim 1, having a braking nczzle, saidconduit means conducting the bypassed air to said braking nozzle.

References Cited in the file of this patent UNITED STATES PATENTS1,986,435 Heinze Jan. 1, 1935 6 ONeil June 24, 1947 Martin May 30, 1950Imbert Oct. 31, 1950 Roy Dec. 11, 1951 Marchant Nov. 10, 1953 Rennie etal Dec. 15, 1953

